[Bug c++/55550] New: internal compiler segmentation fault on openmp for collapse

[Bug c++/55550] New: internal compiler segmentation fault on openmp for collapse

[lucjaulmes at free dot fr]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55550

             Bug #: 55550
           Summary: internal compiler segmentation fault on openmp for
                    collapse
    Classification: Unclassified
           Product: gcc
           Version: 4.6.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: lucjaulmes@free.fr


Here is the error output 
g++-4.7 -std=c++11 -DUSE_OPENMP -g -fopenmp -DVERBOSE=1 BestSolution.cpp
main.cpp Node.cpp SimulatedAnnealing.cpp -o run
Node.cpp: In member function ‘int Node::lowerBound(int, const intMatrix&, const
intMatrix&, const intVector&, const boolVector&)’:
Node.cpp:169:40: internal compiler error: Segmentation fault
Please submit a full bug report, [...]

The choke is on this line, specifically with the value 4 :
#pragma omp parallel for collapse(4)

then follow 4 imbricated for loops of the same size that look like
for(int k=0;k<dim;k++)
    for(int i=...)
        for(int l=...)
            for(int j=...)
                c[k*dim+i][l*dim+j] = f[i][k] * d[j][l];

Running on Linux (Ubuntu 12.04 precise) kernel 3.2.0.29 with a core i7.

Here is the output of my gcc -v :
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.6/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro
4.6.3-1ubuntu5' --with-bugurl=file:///usr/share/doc/gcc-4.6/README.Bugs
--enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-4.6 --enable-shared --enable-linker-build-id
--with-system-zlib --libexecdir=/usr/lib --without-included-gettext
--enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.6
--libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object
--enable-plugin --enable-objc-gc --disable-werror --with-arch-32=i686
--with-tune=generic --enable-checking=release --build=x86_64-linux-gnu
--host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5)

[Bug c++/55550] internal compiler segmentation fault on openmp for collapse

[lucjaulmes at free dot fr]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55550

--- Comment #1 from Luc <lucjaulmes at free dot fr> 2012-11-30 17:25:28 UTC ---
If I manually unfold the loop to 2 stages and use collapse(2), or if I unfold
it to 1 stage and use just a "parallel for" it gives the same error.

The whole loop works fine without this omp pragma line though.

Furthermore, it might be worth mentioning that all these 2D-arrays are actually
std::vector< std::vector<int> >'s

[Bug c++/55550] internal compiler segmentation fault on openmp for collapse

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55550

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING
   Last reconfirmed|                            |2012-11-30
                 CC|                            |jakub at gcc dot gnu.org
     Ever Confirmed|0                           |1

--- Comment #2 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-11-30 17:51:17 UTC ---
Please attach a minimized but self-contained snippet, per the bug reporting
instructions. Thanks.

[Bug c++/55550] internal compiler segmentation fault on openmp for collapse

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55550

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |RESOLVED
         Resolution|                            |INVALID

--- Comment #3 from Paolo Carlini <paolo.carlini at oracle dot com> 2013-05-04 16:36:54 UTC ---
Feedback not forthcoming.